The use of a cyclone, or multiple cyclones connected in parallel or series, is known to be advantageous in the separation of particulate matter from a fluid stream. Currently, many vacuum cleaners, which are sold for residential applications, utilize at least one cyclone as part of the air filtration mechanism.
U.S. Pat. No. 4,826,515 (Dyson) discloses a cyclonic vacuum cleaner having two cyclonic stages, namely a first stage for separating larger particulate matter from an air stream and a second stage for separating finer particulate matter from the same air stream. Each cyclonic stage comprised a single cyclone wherein separated particulate matter was collected in the bottom of the cyclones. Vacuum cleaners, which use a cyclonic cleaning stage comprising a plurality of cyclones in parallel, are also known.
As the cyclonic stage or stages fill, a user should empty the cyclonic stage or stages. Accordingly, the cyclonic stage or stages, or the entire vacuum cleaner, may be transported to a position above a receptacle (e.g. a garbage bin or a drain) and opened so as to allow the dirt or fluid to pour into the receptacle.
In order to inhibit hair and other larger matter from traveling downstream from a cyclone, a shroud, screen or filter is typically placed in covering relationship to the cyclone air outlet. From time to time, the shroud, screen or filter may become clogged and require cleaning.